Research has found it may be possible to undo the damage to muscle in children with a form of motor neurone disease. Newborns with the most severe spinal muscular atrophy fail to cry at birth. Spinal muscular atrophy, also know as ‘floppy baby syndrome’, is the main genetic cause of death in children. One in 6,000 births are affected by spinal muscular atrophy, of which sadly 50% with the most severe form pass away before they reach two years of age.
The University of Edinburgh studied the effect of a drug on mice, which may increase specific protein levels and reverse muscle damage.
Spinal muscular atrophy causes muscle watages, decreased mobility and muscular function. One in 40 people carry the genetic mutation that causes the disease.
At any one time, Spinal Muscular Atrophy affects up to (approximately) 6,000 people in the UK. There are three grades of Spinal Muscular Atrophy:
Type 1 – floppy limbs and “flickering” tongues – the most severe grade
Type 2 – usually picked up in children aged 6-18 months old. Affected children can sit, but not walk.
Type 3 – diagnosed over 2 years old with problems walking and can require a wheelchair – the mildest form.
The mental ability of the child is not affected. Although this disease causes damage to the nerves the Edinburgh research team, led by Tom Gillingwater, professor of neuroanatomy, patients also had unhealthy muscles. They found this destruction can arise even if the nerve connections are healthy. Low levels of a protein called SMN, caused by a genetic mutation resulted in the muscle damage. The muscles’ blood supply is disturbed by the genetic mutation which then leads to further muscle damage.
A second study treated mice who had SMA with a group of drugs called HDAC inhibitors. The treatment targeted the genetic mutation, which resulted in increased protein levels in the muscle.
Prof Gillingwater said: “SMA is the most common genetic cause of infant death in the western world. By showing the important role that muscles play in this disease, we can now focus our efforts on trying to block the disease in all affected tissues of the body.”
Current research is looking at how HDAC or other drugs can be adapted to improve muscle control and blood supply. Lucy Blythe, of the SMA Trust, which funded the research, said: “These findings are significant. This is a tragic condition, because so many babies with type 1 die before the age of two.”